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Approach responses, consummatory behaviors, and directed motor responses maintained by food reward resemble autoshaping CRs and are increased by lower doses of ethanol. This study evaluated the effects of presession i.p. injections of ethanol doses (0.00, 0.25, 0.50, 0.70. or 1.00 g/kg) on the acquisition of lever-press autoshaping CR performance in groups of male Long-Evans hooded rats. Paired groups received 15 daily sessions of Pavlovian autoshaping procedures, wherein the insertion of a retractable lever for 5 s (CS) was followed by the response-independent presentation of food (US). Ethanol facilitated lever-press autoshaping CR acquisition, as revealed by dose-related increases in the number of trials on which CRs were performed. The form of the dose-effect curve was inverted U-shaped with maximal responding induced during sessions 1-5 by the 0.70 g/kg ethanol dose. A similar dose-effect curve was observed during sessions 11-15, revealing that the effects of ethanol on autoshaping CR performance were relatively stable. A pseudoconditioning control group injected presession with 0.50 g/kg ethanol received training wherein the food US was presented randomly with respect to the lever CS. Few lever-presses were performed by the Random 0.50 group, indicating that ethanol's effects on autoshaping CR acquisition and maintenance observed in the Paired 0.50 group were not due to its psychomotor activating effects. A non-injection control group performed more autoshaping CRs than did the control group injected presession with saline, indicating that daily presession i.p. injections per se suppress autoshaping CR performance. Results reveal that low doses of ethanol enhance Pavlovian conditioning of directed motor and consummatory-like responding maintained by food reward. Implications for autoshaping accounts of impulsivity and drug abuse are considered.

Female Long-Evans rats were trained to discriminate d-amphetamine (0.8 mg/kg) vs. saline in a food-reinforced two-lever operant task. Fifteen rats (fast group) acquired the discrimination rapidly, achieving criterion (eight correct choices within ten sessions) during the first 10 sessions (mean sessions to criterion = 10.0). The remaining eight rats (slow group) made at least three errors during the first 10 sessions and required additional drug discrimination training to achieve criterion (mean sessions to criterion = 15.9). When a rat had completed a minimum of 30 two-lever discrimination training sessions and, in addition, provided 10 correct choices within 10 sessions, generalization testing with lower doses of d-amphetamine was initiated. The fast group made more d-amphetamine-appropriate choices during the generalization test and generalized more to the 0.2 mg/kg d-amphetamine test dose than did the slow group, though the number of training sessions prior to generalization testing was comparable across groups. Results suggest that when the training drug is easily discriminated, fast learners generalize more, even when groups receive comparable amounts of training prior to generalization testing, and this effect is observed in female rats.